SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a016ab4115cbdd5a43c07b766ec9291263f1a47ecea11f516f0961f8578735d6' 
  AND token = 'JFjvHQ6T8GDFNBlLAu5WTS6/DqwQN4WvnS0TOZKFOtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}